The present invention relates generally to regulator circuits. More particularly, the present invention relates to an improved regulator circuit that includes two or more amplifiers that are shared to an array of pass circuits.
Integrated circuits are often employed to regulate power. Regulator circuits may be used where the input power source is unregulated or clean power is required in a noisy environment.
A regulator circuit may be used to regulate the power provided by a battery cell. Defects in the regulator circuit can cause the voltage delivered by the battery cell to become unregulated. An unregulated voltage can cause damage to a load or other circuitry.
The present invention is directed to regulator circuits. More particularly, the present invention relates to an improved regulator circuit that includes two or more amplifiers that are arranged in a redundant architecture with an array of pass circuits. The regulator circuit regulates the potential from a source circuit to a reference potential. A shunt stage limits the source potential with a dominant loop that also includes an amplifier circuit and a corresponding bias stage. Each bias stage may include multiple bypass circuits that are arranged such that a defect in any one of the bypass circuits does not effect the operation of the improved regulator circuit. The shunt stage can also include multiple pass circuits such that a defect in any one of the pass circuits does not effect the operation of the improved regulator circuit. Compensation capacitance circuits may be coupled between the bias stages to a high impedance compensation node within each amplifier circuit. If one of the bypass circuits is defective, the compensation capacitors prevent the defect from affecting the operation of the amplifier circuits.
Briefly stated, an apparatus and method for an improved regulator circuit includes multiple amplifier circuits, multiple bias stages, and a shunt stage. Each bias stage includes a set of MOS transistors with respective resistance circuits that are arranged to bias the shunt stage. The shunt stage includes a set of MOS transistor that are arranged to regulate a potential provided by a source circuit when active. Each amplifier circuit forms a regulation loop with a respective MOS transistor of the bias stage and a MOS transistor of the shunt stage. The multiple regulation loops provide redundancy. The regulation loops do not conflict with each other. Failures or defects within one of the regulation loops does not affect the remaining regulation loops in such a way that over-voltage results from the failure. The improved regulator prevents an over-voltage when at least one of the regulation loops is operable.
A more complete appreciation of the present invention and its improvements can be obtained by reference to the accompanying drawings, which are briefly summarized below, to the following detail description of presently preferred embodiments of the invention, and to the appended claims.